Digital communications conducted over wireless communication channels are generally subjected to environmental factors that can adversely impact throughput, required energy, or effective range. Bit error rate is often used to characterize channel conditions. Under poor channel conditions, there is usually a high bit error rate for data communications, while under good channel conditions, the bit error rate for such communications is lower. Consequently, there are many techniques that utilize bit error rate determinations for monitoring throughput and related channel parameters when operating communication systems.
The Open Systems Interconnection (OSI) reference model defines various layers of abstraction for structuring communications. These layers include, among others, the Media Access Control (MAC) layer. In a typical protocol for implementing the MAC layer, data is segmented into packets and the packets transmitted in frames having a particular length. The performance of a MAC layer protocol under given channel conditions can be characterized by transmission delay, defined as the average time spent by a packet while awaiting transmission, and throughput, defined as the fraction of the channel capacity used for data transmissions. Recently, there has been some attention given to the development of techniques to adapt frame length to reflect channel conditions, in an effort to improve performance at the MAC layer. One approach is discussed in a paper entitled ADAPTIVE FRAME LENGTH CONTROL FOR IMPROVING WIRELSS LINK THROUGHPUT, RANGE, AND ENERGY EFFICIENCY, published by Lettieri et al., in the 1998 Institute of Electrical and Electronics Engineers (IEEE) proceedings. Here, the author concluded that performance in wireless networks could improve by manipulating the frame size used to transmit data packets at the MAC layer. In this approach, an approximation of bit error rate on a communication channel is obtained by examining packet error rate, and this approximation is used to select one of “three or four distinct levels of fragmentation over orders of magnitude of bit error rate.” However, this reference uses an empirical approach to determine preferred frame size that is not adequately for many applications.
While it is recognized that adaptive frame sizing could lead to improvements in network performance, particularly for problems related to congestion due to heavy traffic or densely-deployed network, there exists a need for a practical approach for realizing these benefits.